Hey, can you point me in the right direction? I can't find the info on how to make the serial USB adapter. I know BFM has one for sale for $20, but I'd like to make my own.

I know I need a db9 connector, and a serial to usb adapter. My question is how do I hook the wires up to the db9 connector? Is there just one wire for the blue wire coming from the wideband? The pictures of the BFM one looks like two wires. What pins do the hook up to?

Post # 14
I got this out of the manual from my wideband,this explains what todo::

Serial Output

The serial output can be used for data logging when an EFI system is not accessible. To run the data stream, a RS-232 (DB-9) Female Receptacle shall be purchased.

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Figure 5

Wire View of RS-232 (DB-9) Male Plug Two wires need to be connected to a RS-232 serial port. The BLUE wire from the AEM UEGO Gauge shall be connected to Pin #2 (RX) on the serial port for receiving data. Page 7 Pin # 5 (GND) on the serial port shall be grounded. If a standard 9-pin serial cable is to be cut instead, the (RX) wire is typically RED and the (GND) wire is typically GREEN. However, this should be confirmed with a continuity tester before attempting.

(Figure 5)
Use HyperTerminal for testing the data stream. This software is found on most PCs. To find HyperTerminal go to: Start | All Programs | Accessories | Communications | HyperTerminal. Name the New Connection and click OK. Set the COM port to the one being used and click OK.

Verify the settings above and click OK. When power is supplied to the AEM UEGO Gauge, AFR (or Lambda) data will be displayed, as shown below. (Figure 6)

Figure 6

Data logging with Hyper Terminal UEGO Sensor

If attempting to route the UEGO Sensor through a tight space, AEM recommends temporally removing the light grey latch from the Bosch connector, as shown below, or, routing the smaller six pin connector through the hole.